The TARDIS staircase was a vertical pathway between the planetary surface of Earth and the TARDIS when hovering in the sky. The entire structure, when viewed from below, was either invisible or cloaked by a perception filter.

The lowest few metres were traversed via a retractable ladder extending down from a landing, much like a fire escape ladder. Although invisible from the ground, the ladder could be pulled down by someone who knew precisely where it was and could reach it.

The majority of the structure, between the landing and the cloud-top TARDIS, consisted of a spiral staircase. Like the TARDIS itself, the staircase was dimensionally transcendental; a comparatively short climb would traverse considerable altitude. Moreover, the spiral's twist reversed just below its top. For most of the staircase's length, the user climbed up clockwise and down anticlockwise; the top few steps, however, spiralled up anticlockwise and down clockwise. (TV: The Snowmen)

On the evening of 23 December1892, a curious Clara Oswald followed the Doctor and witnessed him pull a ladder down from nowhere before climbing up and disappearing. Minutes later, Clara managed to grab the ladder and pull it to the ground. She knocked on the TARDIS but hid behind it out of sight of the Doctor, before descending back to the surface.